Data buses are used for digital communication between two or more electronic devices. A device connected to a bus is often referred to as a bus node. In general, the expression “bus” usually denotes a communication system which comprises both the specification of the bus hardware and a communication protocol, according to which the bus nodes communicate. Many data buses are standardized, wherein different bus standards prevail in different fields of industry. For example, CAN (Controller Area Network), LIN (Local Interchange Network) and FlexRay are often used in the automotive industry (but also in other industrial fields of use). Said examples are from the category of field buses.
If data transmission between bus nodes in different supply voltage domains (for example 12 V/48 V in automotive applications) is desired in a communication system, galvanic isolation is usually provided in the transmission path. However, galvanic isolation can also be useful for the purpose of overvoltage protection or for other reasons even if different voltage domains having different supply voltages are not used. This galvanic isolation is implemented, for example, by means of components such as optocouplers, integrated coreless transformers, coupling capacitors, etc. Such components can be integrated in bus interface circuits which form an interface between the bus lines and an electronic device, for example a microcontroller. At the same time, the bus interface circuit also forms an interface between two supply voltage domains.
Known bus interface circuits can have a galvanically isolating component, for example an integrated coreless transformer, for each data stream (digital signal) to be transmitted. In many applications, not only the data stream to be transmitted via the bus (uplink data stream) and the data stream received by the bus (downlink data stream) are transmitted via galvanically isolating components within the bus interface circuit but also further signals, for example status and diagnostic signals. Additional galvanically isolating components are used to transmit these signals, which results in a comparatively high chip area requirement in integrated bus interface circuits.